The Osmington shooting was a murder-suicide in Osmington, a small village near Margaret River, Western Australia, on 11 May 2018. The shooting involved the deaths of the extended Miles family, including Peter Miles and his wife Cynda, their daughter Katrina Miles and her four children.

Katrina's estranged husband, Aaron Cockman, had been involved in a lengthy custody battle with his wife, stating Peter and Cynda had prevented him from seeing his children for six months. Police do not believe any person other than the deceased were involved with the deaths.[1]

The shooting has been treated by authorities as a murder-suicide by Peter Miles.[2] It is the worst shooting incident in Australia since the Port Arthur massacre of 1996.[3][4]

Authorities arrived at the Miles' 30-acre farm in Osmington following a call to 000 at 5:15 am.[5] Peter Miles (aged 61) was found outside the property deceased in a chair on the veranda, his wife Cynda (58) inside the main house. Their daughter, Katrina Cockman (35) and her four children (Tay, 13; Rylan, 12; Arye, 10 and Kayden, 8) were found inside a converted shed behind the main house that served as their residence.[6] Western Australia Police Commissioner Chris Dawson confirmed that three rifles were recovered at the property, all of which were licensed to Peter Miles, and that police did not believe that anyone outside the residence was involved.[7]

Aaron Cockman, estranged husband of Katrina and father to their four children, held a press conference 48 hours after learning of the deaths. Cockman said that he had been told by police that Peter Miles first shot Katrina and her four children while they slept in their beds, before shooting his wife Cynda in the living room of their home. He then placed a two minute 000 call to police[8] alerting them to the shootings, before committing suicide.[9]

On 17 May, Dawson confirmed that police had completed forensic work and that access to the property was returned to the family, but stated that the investigation would continue for several months.[10] A suicide note was also confirmed to have been found.[11]